Before 1a57423166 ("cgroup: make hierarchy_id use cyclic idr"),
hierarchy IDs were allocated from 0. As the dummy hierarchy was
always the one first initialized, it got assigned 0 and all other
hierarchies from 1. The patch accidentally changed the minimum
useable ID to 2.
Let's restore ID 0 for dummy_root and while at it reserve 1 for
unified hierarchy.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
kernel/cgroup.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1421,14 +1421,15 @@ static void init_cgroup_root(struct cgro
init_cgroup_housekeeping(cgrp);
}
-static int cgroup_init_root_id(struct cgroupfs_root *root)
+static int cgroup_init_root_id(struct cgroupfs_root *root, int start, int end)
{
int id;
lockdep_assert_held(&cgroup_mutex);
lockdep_assert_held(&cgroup_root_mutex);
- id = idr_alloc_cyclic(&cgroup_hierarchy_idr, root, 2, 0, GFP_KERNEL);
+ id = idr_alloc_cyclic(&cgroup_hierarchy_idr, root, start, end,
+ GFP_KERNEL);
if (id < 0)
return id;
@@ -1631,7 +1632,8 @@ static struct dentry *cgroup_mount(struc
if (ret)
goto unlock_drop;
- ret = cgroup_init_root_id(root);
+ /* ID 0 is reserved for dummy root, 1 for unified hierarchy */
+ ret = cgroup_init_root_id(root, 2, 0);
if (ret)
goto unlock_drop;
@@ -4899,7 +4901,7 @@ int __init cgroup_init(void)
mutex_lock(&cgroup_mutex);
mutex_lock(&cgroup_root_mutex);
- BUG_ON(cgroup_init_root_id(&cgroup_dummy_root));
+ BUG_ON(cgroup_init_root_id(&cgroup_dummy_root, 0, 1));
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&cgroup_mutex);
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/containers
